A typical radar antenna includes an antenna body that is a radiation conductor, and also include a drive source (e.g., electric motor) for rotatably driving the antenna body in the horizontal plane. Moreover, the antenna includes a gear box covered by a housing so that the drive source is not exposed outside.
A general radar antenna is provided with an oscillation source (magnetron) inside the housing of the gear box. Since a general drive source and a general oscillation source produce heat, heat easily accumulates inside the housing.
Moreover, for a radar apparatus, a configuration for accommodating a circuit board for signal processing inside the housing of the gear box has been proposed in recent years. This circuit board is mounted with a CPU for performing predetermined signal processing on signals received by the antenna. By accommodating the circuit board inside the housing of the gear box, there is no need for disposing the circuit board separately from the antenna, and the modularization of the radar antenna can be promoted.
However, since the CPU on the circuit board is a heat generating body, when the circuit board is disposed inside the housing, the problem that the heat easily accumulates inside the housing becomes more severe. Especially, since CPUs are sensitive to heat and there is a high possibility of failure due to the heat or thermal runaway, some sort of countermeasure is required to cool inside the housing.
For this, a configuration for attaching heat release members, such as fins, to an outer surface of the housing of the gear box can be considered. However, in this case, work of attaching the heat release members outside the housing will be required and, additionally, each of the heat generating bodies, such as the drive source, the oscillation source, and the CPU, needs to be attached to the heat release members from inside the housing. Thus, the gear box will be extremely difficult to assemble.
Moreover, since radar antennas are disposed at a high position in many cases, they relatively easily stand out. Therefore, the design thereof is also important. However, since there have been many cases where the design of heat release members, such as fins, is not preferable, the heat release members are avoided from being disposed to the outer surface of the housing of the gear box as much as possible.
For these reasons, it has been desired to efficiently release the heat inside the housing without providing the heat release member, such as fins, to the outer surface of the gear box.
In this regard, JP1992-087402A discloses a configuration including an attaching stand having an air passing duct, an antenna panel supporting stand attached to the attaching stand and for supporting an antenna panel to be spaced from the attaching stand, and a radome covering the antenna panel. In JP1992-087402A, the heat generated by the antenna panel is transmitted from the antenna panel supporting stand to the attaching stand so as to be released by the air passing inside the duct of the attaching stand.
However, JP1992-087402A relates to the heat release of a fixed antenna dedicated to reception, and not to the heat release from a gear box for rotatably driving a radar antenna. Also, with the configuration of JP1992-087402A, since the duct is exposed outside, the design of the entire antenna is degraded.